Help-Concept clarification

Blitz3D Forums/Blitz3D Beginners Area/Help-Concept clarification

augGa

(Posted 2004) [#1]

Elementary..so I thought.. Just trying to vary the back color.. simple: use the ClsColor/Cls combination ..oops..
I obviously do not understand some basic concept with B3D..
code:
Graphics3D 1024,768,16,2
SetBuffer BackBuffer() ;<--- Build in backbuffer

ClsColor 255,0,0 ;red ;<-- next cls sets curr buff to clr
Cls ;<--- set the backbuffer to red

cam=CreateCamera()
cube=CreateCube()
light=CreateLight(1,cam)
PositionEntity cam,0,0,-5
;CameraClsColor cam,255,0,0 ;<---- must have ???

While Not KeyDown(1)
TurnEntity cube,.500,.000,.0

If KeyDown (208) MoveEntity cam, 0, 0, 0.1
If KeyDown (200) MoveEntity cam, 0, 0, -0.1

UpdateWorld()
;WaitKey() ;<------ screen is red before render
RenderWorld() ;<---- turns black ???
;WaitKey()
Flip

If KeyDown(203) TurnEntity cam,0,3,1
If KeyDown(205) TurnEntity cam,0,-3,-1
Wend
End
====
In Playing with it..
the RenderWorld shows the background as black unless the
cameraClsColor is used...
I simply wanted to show a cube on a red background..What is happening ?

Who was John Galt?

(Posted 2004) [#2]

Kurtz you are mixing 2D and 3D commands. The cls sets the background red but when u renderworld, the results paste over the red background. Think the command u r after is cameraclscolor

Update-

Reading your post a bit closer - you figured it out by yourself anyways! You can lose the clscolor and cls commands before the renderworld

augGa

(Posted 2004) [#3]

@Ram-Thanks..
So the concept I am not understanding is:
In 3d the "scene" (Cubes etc..) is NOT being drawn on the BACKBUFFER rather "somewhere(?)" else.. the RenderWorld Puts the "Scene" onto the backbuffer and the FLIP sends the backbuffer to the frontbuffer (visible screen)... Am I close ?

Ross C

(Posted 2004) [#4]

Hey man, use camerclsmode. This stops renderworld from deleting anything prevoius on the screen.

Say you draw a rectangle, then call renderworld, the rectangle will get deleted. BUT if you use cameraclsmode, then you can make renderworld not clear the backbuffer before rendering, so your rectangle will still be in view.

You must however use cls at the top of each loop, or you'll get the stuff from the last loop appearing in the backround :)

PowerPC603

(Posted 2004) [#5]

You could try to use the CameraViewPort command.

Graphics3D 1024,768,16,2 
SetBuffer BackBuffer() ;<--- Build in backbuffer 

ClsColor 255,0,0 ;red ;<-- next cls sets curr buff to clr 
Cls ;<--- set the backbuffer to red 

cam=CreateCamera() 
cube=CreateCube() 
light=CreateLight(1,cam) 
PositionEntity cam,0,0,-5 
;CameraClsColor cam,255,0,0 ;<---- must have ??? 

CameraViewport cam, 100, 100, 824, 568 ; <----------- use this to give it a try

While Not KeyDown(1) 
TurnEntity cube,.500,.000,.0 

If KeyDown (208) MoveEntity cam, 0, 0, 0.1 
If KeyDown (200) MoveEntity cam, 0, 0, -0.1 

UpdateWorld() 
;WaitKey() ;<------ screen is red before render 
RenderWorld() ;<---- turns black ??? 
;WaitKey() 
Flip 

If KeyDown(203) TurnEntity cam,0,3,1 
If KeyDown(205) TurnEntity cam,0,-3,-1 
Wend 
End

If you add the CameraViewPort command (see code),
you can actually see that the backbuffer is still red, like stated in the ClsColor command.
(Using the above code will give you a smaller portion of the screen that's rendered, with a red outline around it)

The only reason the screen goes black, is that the camera has a standard black background where it sees nothing.
And those black parts of the screen overlap the red background color.

Who was John Galt?

(Posted 2004) [#6]

Kurtz- yeah you got it - the scene is not actually drawn at all until you renderworld.